Isoxazole derivatives for use as fungicides

ABSTRACT

The present invention relates to isoxazole compounds of formula (I) having fungicidal activity, to agricultural compositions comprising them, and to the use of said compounds and compositions in agriculture for the control of microbial pests, particularly fungal pests, on plants

This application is a continuation of copending U.S. application Ser.No. 13/133,708, filed on 9 Jun. 2011, herein incorporated by referencein its entirety for all purposes.

The present invention relates to isoxazole compounds having fungicidalactivity, to agricultural compositions comprising them, and to the useof said compounds and compositions in agriculture for the control ofmicrobial pests, particularly fungal pests, on plants.

The incidence of serious fungal infections, either systemic or topical,continues to increase for plants, animals, and humans. Many fungi arecommon in the environment and not harmful to plants or mammals. However,some fungi can produce disease in plants, humans and/or animals.

Fungicides are compounds, of natural or synthetic origin, which act toprotect plants against damage caused by fungi, including oomycetes.Current methods of agriculture rely heavily on the use of fungicides. Infact, some crops cannot be grown usefully without the use of fungicides.Using fungicides allows a grower to increase the yield of the crop andconsequently, increase the value of the crop. Numerous fungicidal agentshave been developed. However, the treatment of fungal infestations andinfections continues to be a major problem. Furthermore, fungicide andantifungal drug resistance has become a serious problem, rendering theseagents ineffective for some agricultural and therapeutic uses. As such,a need exists for the development of new fungicidal and antifungalcompounds (see, e.g., U.S. Pat. No. 6,673,827; See also U.S. Pat. No.6,617,330 to Walter, which describes pyrimidin-4-enamine as fungicides).

International patent application WO2006/031631 refers to a series ofisoxazole derivatives having fungicidal properties. There exists a needtherefore for alternative methods of control of fungi. Preferably, newcompounds may possess improved fungicidal properties, such as improvedefficacy, improved selectivity, lower tendency to generate resistance oractivity against a broader spectrum of fungi. Compounds may be moreadvantageously formulated or provide more efficient delivery andretention at sites of action, or may be more readily biodegradable.Advantageous compounds or their degradation components may generally beless toxic.

It has surprisingly been found that the isoxazole compounds of thepresent invention exhibit unexpected fungicidal activity and aretherefore suitable for use in agriculture as crop protection agents tocombat or prevent fungal infestations, or to control other pests such asweeds, insects, or acarids that are harmful to crops.

Accordingly, in a first aspect, the present invention provides acompound of formula (I)

wherein R¹ is H or acyl, preferably H;or an agrochemically acceptable salt thereof.

Acyl includes any readily hydrolysable acyl groups, and comprises, forexample, C(O)R², C(O)OR², C(O)NHR² and C(O)NR²R³, wherein R² and R³ areeach independently selected from alkyl, alkenyl, akynyl, heterocyclyl,aryl and heteroaryl. Acyl groups may be optionally substituted with oneor more, for example 1, 2, 3 or 4, halo or OR² groups. Preferred acylgroups are acetyl, benzoyl and phenylacetyl.

Alkyl groups may be straight, branched or cyclic and contain 1 to 24carbon atoms. Preferred alkyl groups may contain 1 to 10 carbon atoms,more preferably 1 to 6 carbons, even more preferably 1 to 4 carbonatoms. Representative alkyl groups include, for example, methyl, ethyl,isopropyl, n-propyl, n-butyl, t-butyl, t-amyl, 2,5-dimethylhexyl,cyclobutyl, cyclopropyl, cyclopentyl and cyclohexyl.

Heterocyclyl groups may contain from 3 to 10 ring-atoms up to 4 of whichmay be hetero-atoms such as nitrogen, oxygen and sulfur, and may besaturated or partially unsaturated. Examples of heterocyclyl groups areoxiranyl, azetidinyl, tetrahydrofuranyl, thiolanyl, pyrrolidinyl,pyrrolinyl, imidazolidinyl, imidazolinyl, sulfolanyl, dioxolanyl,dihydropyranyl, tetrahydropyranyl, piperidinyl, pyrazolinyl,pyrazolidinyl, dioxanyl, morpholinyl, dithianyl, thiomorpholinyl,piperazinyl, azepinyl, oxazepinyl, thiazepinyl, thiazolinyl anddiazapanyl.

Aryl includes phenyl, naphthyl, anthracenyl and phenanthrenyl.

Heteroaryl groups may contain from 3 to 10 ring-atoms up to 4 of whichmay be hetero-atoms such as nitrogen, oxygen and sulfur. Examples ofheteroaryl groups are furyl, thienyl, pyrrolyl, oxazolyl, thiazolyl,imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl,thiadiazolyl, pyridyl, pyrimidinyl, pyrazinyl, pyridazinyl, tetrazolyl,triazinyl. In addition, the term heteroaryl includes fused heteroarylgroups, for example benzimidazolyl, benzoxazolyl, imidazopyridinyl,benzoxazinyl, benzothiazinyl, oxazolopyridinyl, benzofuranyl,quinolinyl, quinazolinyl, quinoxalinyl, benzothiazolyl, phthalimido,benzofuranyl, benzodiazepinyl, indolyl and isoindolyl.

Halo means fluoro, chloro, bromo or iodo.

The compounds of the invention include compounds of formula (I) ashereinbefore defined, polymorphs, and isomers thereof, includingoptical, geometric and tautomeric isomers, and isotopically-labeledcompounds of formula (I).

Agrochemically acceptable salts possess a cation, which is known andaccepted in the art for the formation of salts for agricultural orhorticultural use. Preferably the salts are water-soluble.

Suitable salts of the compounds of formula (I) include acid additionsalts such as those with an inorganic acid such as hydrochloric,hydrobromic, sulphuric, nitric or phosphoric acid, or an organiccarboxylic acid such as oxalic, tartaric, lactic, butyric, toluic,hexanoic or phthalic acid, or a sulphonic acid such as methane, benzeneor toluene sulphonic acid. Other examples of organic carboxylic acidsinclude haloacids such as trifluoroacetic acid.

N-oxides are oxidised forms of tertiary amines or oxidised forms ofnitrogen containing heteroaromatic compounds. They are described in manybooks for example in “Heterocyclic N-oxides” by Angelo Albini and SilvioPietra, CRC Press, Boca Raton, Fla., 1991.

In a preferred embodiment, the present invention provides a compositioncomprising a compound of formula (I), or an agrochemically acceptablesalt thereof, and an agrochemically acceptable diluent or carrier.References to compounds of the invention herein shall be deemed toinclude both a compound of formula (I) and agrochemically acceptablesalts thereof.

The compound of formula (I) exists as a racemate comprising (R) and(S)-enantiomers. The (S)-enantiomer has been found to have significantlygreater fungicidal activity compared to the (R)-enantiomer.

Accordingly, in a preferred aspect, the present invention additionallyprovides the (S)-enantiomers of the compound of formula (I)

wherein R¹ is H or acyl, preferably H;or an agrochemically acceptable salt thereof.

Accordingly, in a preferred aspect, there is provided a compositioncomprising a compound of formula (S)-(I), or an agrochemicallyacceptable salt thereof, and an agrochemically acceptable diluent orcarrier.

Preferably, the compound of formula (S)-(I) is provided as a singleenantiomer having an enantiomeric excess (e.e.) of at least 40%, forexample, at least 50%, 60%, 70% or 80%, preferably at least 90%, morepreferably at least 95%, yet more preferably at least 98% and mostpreferably at least 99%.

Most preferably, the compound of formula (I) is(S)-[3-(4-chloro-2-fluorophenyl)-5-(2,4-difluorophenyl)isoxazol-4-yl]pyridin-3-yl-methanol(Example 2)

Example 2

or an agrochemically acceptable salt thereof.

Preferably, the compound of Example 2 is provided as a single enantiomerhaving an enantiomeric excess (e.e.) of at least 40%, for example, atleast 50%, 60%, 70% or 80%, preferably at least 90%, more preferably atleast 95%, yet more preferably at least 98% and most preferably at least99%.

The compounds and compositions of the present invention are useful forprotecting plants against diseases that are caused by fungi, includingoomycetes. The compounds of the invention can be used in theagricultural sector and related fields as active ingredients forcontrolling plant pests. The compounds of the invention can be used toinhibit or destroy the pests that occur on plants or parts of plants(fruit, blossoms, leaves, stems, tubers, roots) of different crops ofuseful plants, optionally while at the same time protecting also thoseparts of the plants that grow later e.g. from phytopathogenicmicro-organisms.

The compounds and compositions of the present invention may be used asdressing agents for the treatment of plant propagation material, inparticular of seeds (fruit, tubers, grains) and plant cuttings (e.g.rice), for the protection against fungal infections as well as againstphytopathogenic fungi occurring in the soil.

In an additional aspect, the present invention provides a method ofcontrolling or preventing infestation of cultivated plants by pathogenicmicroorganisms, comprising applying a compound of formula (I) orcomposition thereof to said plants, parts thereof or the locus thereofin an amount effective to control said microorganisms.

The compounds and compositions of the present invention may be usedagainst phytopathogenic fungi, for example, those of the followingclasses: Fungi imperfecti (e.g. Botrytis, Pyricularia, Heiminthosporium,Fusarium, Septoria, Cercospora and Alternaria) and Basidiomycetes (e.g.Rhizoctonia, Hemileia, Puccinia). Additionally, they may also be usedagainst the Ascomycetes classes (e.g. Venturia and Erysiphe,Podosphaera, Monilinia, Uncinula) and of the Oomycetes classes (e.g.Phytophthora, Pythium, Plasmopara). Specific examples of fungi that maybe treated include, but are not limited to, Septoria tritici,Stagonospora nodorum, Phytophthora infestans, Botrytis cinerea,Sclerotinia homoeocarpa and Puccinia recondita.

In a preferred embodiment of the invention, the compounds andcompositions of the present invention are used against the fungalorganism Septoria tritici.

The crops of useful plants to be protected typically comprise, forexample, the following species of plants: cereals (wheat, barley, rye,oats, maize (including field corn, pop corn and sweet corn), rice,sorghum and related crops); beet (sugar beet and fodder beet);leguminous plants (beans, lentils, peas, soybeans); oil plants (rape,mustard, sunflowers); cucumber plants (marrows, cucumbers, melons);fibre plants (cotton, flax, hemp, jute); vegetables (spinach, lettuce,asparagus, cabbages, carrots, eggplants, onions, pepper, tomatoes,potatoes, paprika, okra); plantation crops (bananas, fruit trees, rubbertrees, tree nurseries), ornamentals (flowers, shrubs, broad-leaved treesand evergreens, such as conifers); as well as other plants such asvines, bushberries (such as blueberries), caneberries, cranberries,peppermint, rhubarb, spearmint, sugar cane and turf grasses including,for example, cool-season turf grasses (for example, bluegrasses (PoaL.), such as Kentucky bluegrass (Poa pratensis L.), rough bluegrass (Poatrivialis L.), Canada bluegrass (Poa compressa L.) and annual bluegrass(Poa annua L.); bentgrasses (Agrostis L.), such as creeping bentgrass(Agrostis palustris Huds.), colonial bentgrass (Agrostis tenius Sibth.),velvet bentgrass (Agrostis canina L.) and redtop (Agrostis alba L.);fescues (Festuca L.), such as tall fescue (Festuca arundinacea Schreb.),meadow fescue (Festuca elatior L.) and fine fescues such as creeping redfescue (Festuca rubra L.), chewings fescue (Festuca rubra var. commutateGaud.), sheep fescue (Festuca ovina L.) and hard fescue (Festucalongifolia); and ryegrasses (Lolium L.), such as perennial ryegrass(Lolium perenne L.) and annual (Italian) ryegrass (Lolium multiflorumLam.)) and warm-season turf grasses (for example, Bermudagrasses(Cynodon L. C. Rich), including hybrid and common Bermudagrass;Zoysiagrasses (Zoysia Willd.), St. Augustinegrass (Stenotaphrumsecundatum (Walt.) Kuntze); and centipedegrass (Eremochloa ophiuroides(Munro.) Hack.)).

The crops of useful plants also includes plants that have been renderedtolerant to herbicides like bromoxynil or classes of herbicides (such asHPPD inhibitors, ALS inhibitors; for example primisulfuron, prosulfuronand trifloxysulfuron, EPSPS(5-enol-pyrovyl-shikimate-3-phosphate-synthase) inhibitors, GS(glutamine synthetase) inhibitors or PPO (protoporphyrinogen-oxidase)inhibitors) as a result of conventional methods of breeding or geneticengineering. An example of a crop that has been rendered tolerant toimidazolinones (e.g. imazamox) by conventional methods of breeding(mutagenesis) is Clearfield® summer rape (Canola). Examples of cropsthat have been rendered tolerant to herbicides or classes of herbicidesby genetic engineering methods include glyphosate- andglufosinate-resistant maize varieties commercially available under thetrade names RoundupReady®, Herculex I® and LibertyLink®.

The crops of useful plants also includes plants which have been sotransformed by the use of recombinant DNA techniques that they arecapable of synthesising one or more selectively acting toxins, such asare known from toxin-producing bacteria, especially those of the genusBacillus.

The crops of useful plants also includes plants which have been sotransformed by the use of recombinant DNA techniques that they arecapable of synthesising antipathogenic substances having a selectiveaction, such as the so-called “pathogenesis-related proteins” (PRPs, seee.g. European patent application EP 0,392,225). Examples of suchantipathogenic substances and transgenic plants capable of synthesisingsuch antipathogenic substances are known, for example, from Europeanpatent applications EP 0,392,225 and EP 0,353,191, and Internationalpatent application WO 95/33818. The methods of producing such transgenicplants are generally known to the person skilled in the art and aredescribed, for example, in the publications mentioned above.

In a preferred embodiment of the invention, the crops of useful plantsare selected from cereals, rice, beets, leguminous plants, oil plants,cucumber plants, fibre plants, vegetables, plantation crops,ornamentals, vines, bushberries, caneberries, cranberries, peppermint,rhubarb, spearmint, sugar cane and turf grasses.

The compounds and compositions of the present invention can be appliedto the crop area or plant to be treated, simultaneously or in successionwith further compounds. These further compounds can be, for example,fertilizers or micronutrient donors or other preparations whichinfluence the growth of plants. They can also be selective herbicides aswell as insecticides, fungicides, bactericides, nematicides,molluscicides, plant growth regulators, plant activators or mixtures ofseveral of these preparations, if desired together with furthercarriers, surfactants or application promoting adjuvants customarilyemployed in the art of formulation.

The compounds of the present invention can be mixed with otherfungicides, resulting in some cases in unexpected synergisticactivities.

Mixing components which are particularly preferred are azoles such asazaconazole, bitertanol, propiconazole, difenoconazole, diniconazole,cyproconazole, epoxiconazole, fluquinconazole, flusilazole, flutriafol,hexaconazole, imazalil, imibenconazole, ipconazole, tebuconazole,tetraconazole, fenbuconazole, metconazole, myclobutanil, perfurazoate,penconazole, bromuconazole, pyrifenox, prochloraz, triadimefon,triadimenol, triflumizole or triticonazole; pyrimidinyl carbinoles suchas ancymidol, fenarimol or nuarimol; 2-amino-pyrimidine such asbupirimate, dimethirimol or ethirimol; morpholines such as dodemorph,fenpropidin, fenpropimorph, spiroxamin or tridemorph; anilinopyrimidinessuch as cyprodinil, pyrimethanil or mepanipyrim; pyrroles such asfenpiclonil or fludioxonil; phenylamides such as benalaxyl, furalaxyl,metalaxyl, R-metalaxyl, ofurace or oxadixyl; benzimidazoles such asbenomyl, carbendazim, debacarb, fuberidazole or thiabendazole;dicarboximides such as chlozolinate, dichlozoline, iprodine,myclozoline, procymidone or vinclozolin; carboxamides such as carboxin,fenfuram, flutolanil, mepronil, oxycarboxin or thifluzamide; guanidinessuch as guazatine, dodine or iminoctadine; strobilurines such asazoxystrobin, kresoxim-methyl, metominostrobin, pyraclostrobin,picoxystrobin, SSF-129, methyl2[(2-trifluoromethyl)-pyrid-6-yloxymethyl]-3-methoxy-acrylate or2-[{.alpha.[(.alpha.-methyl-3-trifluoromethyl-benzyl)imino]-oxy}-o-tolyl]-glyoxylicacid-methylester-O-methyloxime (trifloxystrobin); dithiocarbamates suchas ferbam, mancozeb, maneb, metiram, propineb, thiram, zineb or ziram;N-halomethylthio-dicarboximides such as captafol, captan, dichlofluanid,fluoromide, folpet or tolyfluanid; copper compounds such as Bordeauxmixture, copper hydroxide, copper oxychloride, copper sulfate, cuprousoxide, mancopper or oxine-copper; nitrophenol derivatives such asdinocap or nitrothal-isopropyl; organo phosphorous derivatives such asedifenphos, iprobenphos, isoprothiolane, phosdiphen, pyrazophos ortoclofos-methyl; and other compounds of diverse structures such asacibenzolar-S-methyl, harpin, anilazine, blasticidin-S, chinomethionat,chloroneb, chlorothalonil, cymoxanil, dichlone, diclomezine, dicloran,diethofencarb, dimethomorph, dithianon, etridiazole, famoxadone,fenamidone, fentin, ferimzone, fluazinam, flusulfamide, fenhexamid,fosetyl-aluminium, hymexazol, kasugamycin, methasulfocarb, pencycuron,phthalide, polyoxins, probenazole, propamocarb, pyroquilon, quinoxyfen,quintozene, sulfur, triazoxide, tricyclazole, triforine, validamycin,(S)-5-methyl-2-methylthio-5-phenyl-3-phenylamino-3,5-di-hydroimidazol-4-one(RPA 407213),3,5-dichloro-N-(3-chloro-1-ethyl-1-methyl-2-oxopropyl)-4-methylbenzamide(RH-7281), N-allyl-4,5-dimethyl-2-trimethylsilylthiophene-3-carboxamide(MON 65500),4-chloro-4-cyano-N,N-dimethyl-5-p-tolylimidazole-1-sulfon-amide (1KF-916),N-(1-cyano-1,2-dimethylpropyl)-2-(2,4-dichlorophenoxy)-propionamide (AC382042) or iprovalicarb (SZX 722).

The compounds of the present invention can be mixed with one or moresystemically acquired resistance inducer (“SAR” inducer), alone or incombination with a fungicide as above. SAR inducers are known anddescribed in, for example, U.S. Pat. No. 6,919,298. In general, a SARinducer is any compound which has the ability to turn on resistance in aplant to a disease-causing agent, including, but not limited to a virus,a bacterium, a fungus, or combinations of these agents. In addition, anSAR inducer may induce resistance to insect feeding in a plant, asdefined by Enyedi et al. (1992; Cell 70: 879-886). Exemplary SARinducers cover many structural families of compounds, but are united bytheir ability to induce a resistance to plant diseases and/or pestfeeding. One class of SAR inducers is the salicylates. The commercialSAR inducers acibenzolar-s-methyl (available as Actigard® fromSyngenta), harpin protein (available as Messenger™ from EdenBiosciences), yeast extract hydrolysate from Saccharomyces cerevisiae(available as Keyplex® 350-DP® from Morse Enterprises Limited, Inc. ofMiami, Fla.), and Oryzemate are useful in the present invention.Elicitors, including the Goemar products are another class of SARinducers that can also be used. In addition, ethylene, its biosyntheticprecursors, or ethylene releasing compounds such as Ethrel areconsidered SAR inducers of utility in this context.

Suitable carriers and adjuvants can be solid or liquid and aresubstances useful in formulation technology, e.g. natural or regeneratedmineral substances, solvents, dispersants, wetting agents, tackifiers,thickeners, binders or fertilizers.

A preferred method of application of the compounds and compositions ofthe present invention is foliar application. The frequency ofapplication and the rate of application will depend on the risk ofinfestation by the corresponding pathogen. However, the compounds of thepresent invention can also penetrate the plant through the roots via thesoil (systemic action) by drenching the locus of the plant with a liquidformulation, or by applying the compounds in solid form to the soil,e.g. in granular form (soil application). In crops of water such asrice, such granulates can be applied to the flooded rice field. Thecompounds and compositions of the present invention may also be appliedto seeds (coating) by impregnating the seeds or tubers either with aliquid formulation of the fungicide or coating them with a solidformulation.

The term locus as used herein is intended to embrace the fields on whichthe treated crop plants are growing, or where the seeds of cultivatedplants are sown, or the place where the seed will be placed into thesoil. The term seed is intended to embrace plant propagating materialsuch as cuttings, seedlings, seeds, and germinated or soaked seeds.

The term plant propagation material means the generative parts of aplant including seeds of all kinds (fruit, tubers, bulbs, grains etc),roots, rhizomes, cuttings, cut shoots and the like. Plant propagationmaterial may also include plants and young plants which are to betransplanted after germination or after emergence from the soil.

The compounds of the present invention may be used in unmodified formor, preferably, together with the adjuvants conventionally employed inthe art of formulation. To this end they are conveniently formulated inknown manner to as granules, wettable or soluble powders, emulsifiableconcentrates, coatable pastes, dusts, flowables, directly sprayable ordilutable solutions, suspensions or emulsions, or as controlled releaseforms such as microcapsules. As with the type of the compositions, themethods of application, such as spraying, atomizing, dusting,scattering, coating or pouring, are chosen in accordance with theintended objectives and the prevailing circumstances.

The compositions of the present invention and, if desired, a solid orliquid adjuvant, are prepared in known manner, typically by intimatelymixing and/or grinding the compound with extenders, e.g. solvents, solidcarriers and, optionally, surface active compounds (surfactants).

Suitable carriers and adjuvants may be solid or liquid and correspond tothe substances ordinarily employed in formulation technology, such as,e.g. natural or regenerated mineral substances, solvents, dispersants,wetting agents, tackifiers, thickeners binding agents or fertilizers.Such carriers are for example described in WO 97/33890.

The agrochemical compositions will usually contain from 0.1 to 99% byweight, preferably from 0.1 to 95% by weight, of the compound of formula(I), 99.9 to 1% by weight, preferably 99.8 to 5% by weight, of a solidor liquid adjuvant, and from 0 to 25% by weight, preferably from 0.1 to25% by weight, of a surfactant.

Whereas it is preferred to formulate commercial products asconcentrates, the end user will normally use dilute formulations.

The compositions may also contain further adjuvants such as stabilizers,antifoams, viscosity regulators, binders or tackifiers as well asfertilizers, micronutrient donors or other formulations for obtainingspecial effects.

Suitably, the agrochemical compositions of the present invention areapplied prior to disease development. Rates and frequency of use of theformulations are those conventionally used in the art and will depend onthe risk of infestation by the fungal pathogen, the developmental stageof the plant and on the location, timing and application method.Advantageous rates of application are normally from 5 g to 2 kg ofactive ingredient (a.i.) per hectare (ha), preferably from 10 g to 1 kga.i./ha, most preferably from 20 g to 600 g a.i./ha. When used as seeddrenching agent, convenient rates of application are from 10 mg to 1 gof active substance per kg of seeds.

Suspension concentrates are aqueous formulations in which finely dividedsolid particles of the active compound are suspended. Such formulationsinclude anti-settling agents and dispersing agents and may furtherinclude a wetting agent to enhance activity as well an anti-foam and acrystal growth inhibitor. In use, these concentrates are diluted inwater and normally applied as a spray to the area to be treated. Theamount of active ingredient may range from 0.5% to 95% of theconcentrate.

Wettable powders are in the form of finely divided particles whichdisperse readily in water or other liquid carriers. The particlescontain the active ingredient retained in a solid matrix. Typical solidmatrices include fuller's earth, kaolin clays, silicas and other readilywet organic or inorganic solids. Wettable powders normally contain from5% to 95% of the active ingredient plus a small amount of wetting,dispersing or emulsifying agent.

Emulsifiable concentrates are homogeneous liquid compositionsdispersible in water or other liquid and may consist entirely of theactive compound with a liquid or solid emulsifying agent, or may alsocontain a liquid carrier, such as xylene, heavy aromatic naphthas,isophorone and other non-volatile organic solvents. In use, theseconcentrates are dispersed in water or other liquid and normally appliedas a spray to the area to be treated. The amount of active ingredientmay range from 0.5% to 95% of the concentrate.

Granular formulations include both extrudates and relatively coarseparticles and are usually applied without dilution to the area in whichcontrol of plant pathogenic fungi is required. Typical carriers forgranular formulations include sand, fuller's earth, attapulgite clay,bentonite clays, montmorillonite clay, vermiculite, perlite, calciumcarbonate, brick, pumice, pyrophyllite, kaolin, dolomite, plaster, woodflour, ground corn cobs, ground peanut hulls, sugars, sodium chloride,sodium sulphate, sodium silicate, sodium borate, magnesia, mica, ironoxide, zinc oxide, titanium oxide, antimony oxide, cryolite, gypsum,diatomaceous earth, calcium sulphate and other organic or inorganicmaterials which absorb or which can be coated with the active compound.Granular formulations normally contain 5% to 25% of active ingredientswhich may include surface-active agents such as heavy aromatic naphthas,kerosene and other petroleum fractions, or vegetable oils; and/orstickers such as dextrins, glue or synthetic resins.

Dusts are free-flowing admixtures of the active ingredient with finelydivided solids such as talc, clays, flours and other organic andinorganic solids which act as dispersants and carriers.

Microcapsules are typically droplets or granules of the activeingredient enclosed in an inert porous shell which allows escape of theenclosed material to the surroundings at controlled rates. Encapsulateddroplets are typically 1 to 50 microns in diameter. The enclosed liquidtypically constitutes 50 to 95% of the weight of the capsule and mayinclude solvent in addition to the active compound. Encapsulatedgranules are generally porous granules with porous membranes sealing thegranule pore openings, retaining the active species in liquid forminside the granule pores. Granules typically range from 1 millimetre to1 centimetre and preferably 1 to 2 millimetres in diameter. Granules areformed by extrusion, agglomeration or prilling, or are naturallyoccurring. Examples of such materials are vermiculite, sintered clay,kaolin, attapulgite clay, sawdust and granular carbon. Shell or membranematerials include natural and synthetic rubbers, cellulosic materials,styrene-butadiene copolymers, polyacrylonitriles, polyacrylates,polyesters, polyamides, polyureas, polyurethanes and starch xanthates.

Other useful formulations for agrochemical applications include simplesolutions of the active ingredient in a solvent in which it iscompletely soluble at the desired concentration, such as acetone,alkylated naphthalenes, xylene and other organic solvents. Pressurisedsprayers, wherein the active ingredient is dispersed in finely-dividedform as a result of vaporisation of a low boiling dispersant solventcarrier, may also be used.

Suitable agricultural adjuvants and carriers that are useful informulating the compositions of the invention in the formulation typesdescribed above are well known to those skilled in the art.

Liquid carriers that can be employed include, for example, water,toluene, xylene, petroleum naphtha, crop oil, acetone, methyl ethylketone, cyclohexanone, acetic anhydride, acetonitrile, acetophenone,amyl acetate, 2-butanone, chlorobenzene, cyclohexane, cyclohexanol,alkyl acetates, diacetonalcohol, 1,2-dichloropropane, diethanolamine,p-diethylbenzene, diethylene glycol, diethylene glycol abietate,diethylene glycol butyl ether, diethylene glycol ethyl ether, diethyleneglycol methyl ether, N,N-dimethyl formamide, dimethyl sulfoxide,1,4-dioxane, dipropylene glycol, dipropylene glycol methyl ether,dipropylene glycol dibenzoate, diproxitol, alkyl pyrrolidinone, ethylacetate, 2-ethyl hexanol, ethylene carbonate, 1,1,1-trichloroethane,2-heptanone, alpha pinene, d-limonene, ethylene glycol, ethylene glycolbutyl ether, ethylene glycol methyl ether, gamma-butyrolactone,glycerol, glycerol diacetate, glycerol monoacetate, glycerol triacetate,hexadecane, hexylene glycol, isoamyl acetate, isobornyl acetate,isooctane, isophorone, isopropyl benzene, isopropyl myristate, lacticacid, laurylamine, mesityl oxide, methoxy-propanol, methyl isoamylketone, methyl isobutyl ketone, methyl laurate, methyl octanoate, methyloleate, methylene chloride, m-xylene, n-hexane, n-octylamine,octadecanoic acid, octyl amine acetate, oleic acid, oleylamine,o-xylene, phenol, polyethylene glycol (PEG400), propionic acid,propylene glycol, propylene glycol monomethyl ether, p-xylene, toluene,triethyl phosphate, triethylene glycol, xylene sulfonic acid, paraffin,mineral oil, trichloroethylene, perchloroethylene, ethyl acetate, amylacetate, butyl acetate, methanol, ethanol, isopropanol, and highermolecular weight alcohols such as amyl alcohol, tetrahydrofurfurylalcohol, hexanol, octanol, etc., ethylene glycol, propylene glycol,glycerine and N-methyl-2-pyrrolidinone. Water is generally the carrierof choice for the dilution of concentrates.

Suitable solid carriers include, for example, talc, titanium dioxide,pyrophyllite clay, silica, attapulgite clay, kieselguhr, chalk,diatomaxeous earth, lime, calcium carbonate, bentonite clay, fuller'searth, cotton seed hulls, wheat flour, soybean flour, pumice, woodflour, walnut shell flour and lignin.

A broad range of surface-active agents are advantageously employed inboth said liquid and solid compositions, especially those designed to bediluted with carrier before application. These agents, when used,normally comprise from 0.1% to 15% by weight of the formulation. Theycan be anionic, cationic, non-ionic or polymeric in character and can beemployed as emulsifying agents, wetting agents, suspending agents or forother purposes. Typical surface active agents include salts of alkylsulfates, such as diethanolammonium lauryl sulphate; alkylarylsulfonatesalts, such as calcium dodecylbenzenesulfonate; alkylphenol-alkyleneoxide addition products, such as nonylphenol-C.sub. 18 ethoxylate;alcohol-alkylene oxide addition products, such as tridecylalcohol-C.sub. 16 ethoxylate; soaps, such as sodium stearate;alkylnaphthalenesulfonate salts, such as sodiumdibutylnaphthalenesulfonate; dialkyl esters of sulfosuccinate salts,such as sodium di(2-ethylhexyl) sulfosuccinate; sorbitol esters, such assorbitol oleate; quaternary amines, such as lauryl trimethylammoniumchloride; polyethylene glycol esters of fatty acids, such aspolyethylene glycol stearate; block copolymers of ethylene oxide andpropylene oxide; and salts of mono and dialkyl phosphate esters.

Other adjuvants commonly utilized in agricultural compositions includecrystallisation inhibitors, viscosity modifiers, suspending agents,spray droplet modifiers, pigments, antioxidants, foaming agents,anti-foaming agents, light-blocking agents, compatibilizing agents,antifoam agents, sequestering agents, neutralising agents and buffers,corrosion inhibitors, dyes, odorants, spreading agents, penetrationaids, micronutrients, emollients, lubricants and sticking agents.

In addition, further, other biocidally active ingredients orcompositions may be combined with the compound of formula (I) and usedin the methods of the invention and applied simultaneously orsequentially with the compound of formula (I). When appliedsimultaneously, these further active ingredients may be formulatedtogether with the compound of formula (I) or mixed in, for example, thespray tank. These further biocidally active ingredients may befungicides, herbicides, insecticides, bactericides, acaricides,nematicides and/or plant growth regulators.

Accordingly, the present invention provides a composition comprising acompound of formula (I) and (i) a fungicide, (ii) a herbicide, (iii) aninsecticide, (iv) a bactericide, (v) an acaricide, (vi) a nematicideand/or (vii) a plant growth regulator.

Additionally, the present invention provides for the use of acomposition in the methods of the present invention, said compositioncomprising a compound of formula (I) and (i) a fungicide, (ii) aherbicide, (iii) an insecticide, (iv) a bactericide, (v) an acaricide,(vi) a nematicide and/or (vii) a plant growth regulator.

The compounds and combinations of the present invention may also be usedfor controlling fungal infection (particularly by mold and mildew) oftechnical materials, including protecting technical material againstattack of fungi and reducing or eradicating fungal infection oftechnical materials after such infection has occurred. Technicalmaterials include, for example, organic and inorganic materials wood,paper, leather, natural and synthetic fibers, composites thereof such asparticle board, plywood, wall-board and the like, woven and non-wovenfabrics, construction surfaces and materials, cooling and heating systemsurfaces and materials, ventilation and air conditioning system surfacesand materials, and the like. The compounds and combinations according tothe present invention can be applied to such materials or surfaces in anamount effective to inhibit or prevent disadvantageous effects such asdecay, discoloration or mold in like manner as described above.Structures and dwellings constructed using or incorporating technicalmaterials in which such compounds or combinations have been applied arelikewise protected against attack by fungi.

Accordingly, in a further aspect, the present invention provides amethod of controlling or preventing infestation of technical materialsby pathogenic microorganisms, comprising applying a compound of formula(I) or composition thereof said technical materials, parts thereof orthe locus thereof in an amount effective to control said microorganisms.

The compounds and combinations of the present invention may also be usedin the treatment of fungal infections of human and animal subjects, suchas horses, cattle, sheep, dogs, cats) for medical and veterinarypurposes. Examples of such infections include Onychomycosis,sporotichosis, hoof rot, jungle rot, Pseudallescheria boydii,scopulariopsis or athletes foot, sometimes generally referred to as“white-line” disease, as well as fungal infections in immunocomprisedpatients such as AIDS patients and transplant patients. Thus, fungalinfections may be of skin or of keratinaceous material such as hair,hooves, or nails, as well as systemic infections such as those caused byCandida spp., Cryptococcus neoformans, and Aspergillus spp., such as asin pulmonary aspergillosis and Pneumocystis carinii pneumonia. Thecompounds and combinations of the present invention may be combined witha pharmaceutically acceptable carrier and administered or applied tosuch subjects or infections (e.g., topically, parenterally) in an amounteffective to treat the infection in accordance with known techniques.

Accordingly, in a further aspect, the present invention provides amethod of treating a fungal infection in a subject in need thereof,comprising administering a compound of formula (I) or compositionthereof to said subject in an amount effective to treat said fungalinfection.

Compounds of formula (I) may be prepared using the methods below.

Isoxazoles in which R¹≠H may be prepared from (I) (R¹=H) using standardacylation or carbamoylation conditions. For example, the acetatederivative of (I) (R¹=COCH₃) may be synthesised from the alcohol (I)(R¹=H) by reaction with acetic anhydride and pyridine in ether solventat room temperature overnight. Acylations may be carried out usingeither acid anhydrides (e.g. acetic anhydride, propionic anhydride) oracid chlorides (e.g. benzoyl chloride) in the presence of an organicbase in an inert solvent (e.g. ether, dichloromethane). Carbamoylationsare effected by treating alcohols (I) with a strong base such as sodiumhydride followed by a carbamoyl chloride (e.g. N,N-dimethylcarbamoylchloride) in an inert solvent such as DMF (dimethylformamide).

Example 1[3-(4-Chloro-2-fluorophenyl)-5-(2,4-difluorophenyl)isoxazol-4-yl]pyridin-3-yl-methanol(i) Preparation of 3-(2,4-difluorophenyl)-1-pyridin-3-yl-propynone (3)

1-Ethynyl-2,4-difluorobenzene (24 g, 0.17 mol) was dissolved in THF (350ml) and the reaction mixture was cooled at −78° C. A solution of n-BuLi,2.5 M in hexane, (76.5 ml, 0.19 mol) was added dropwise over 70 minutesmaintaining the temperature below −70° C. The mixture was stirred atthis temperature for a further 10 minutes after the addition wasfinished. A solution of the Weinreb amide 2 (prepared according to WO05/097760, Letters in Organic Chemistry, 4, 20, 2007) (28.9 g, 0.17 mol)in THF (100 ml) was added dropwise over 20 minutes to the solution abovekeeping the temperature below −70° C. The mixture was now warmed to −50°C. obtaining a solution that was further stirred for 1 hour at thistemperature. The reaction mixture was quenched with a saturated solutionof ammonium chloride (100 ml) and allowed to warm to room temperature.The reaction was then poured into a mixture of ethyl acetate/water.Successively, the aqueous phase was washed twice with ethyl acetate. Thecombined organic layers were washed with brine, dried over sodiumsulphate, filtered and concentrated. The crude was recrystallised fromdiethyl ether obtaining 28 g of the desired product. The mother liquorswere concentrated and the residue was purified by column chromatographyon alumina using a mixture of cyclohexane/ethyl acetate 3:1. Totally,29.8 g (70%) of brown compound were obtained.

¹H NMR (CDCl₃): δ 7.02 (m, 1), 7.58 (m, 1), 7.71 (m, 1), 8.56 (m, 1)8.90 (m, 1) and 9.48 ppm (m, 1). MS m/z: 244.0 (M+H).

(ii) Preparation of[3-(4-chloro-2-fluorophenyl)-5-(2,4-difluorophenyl)isoxazol-4-yl]pyridin-3-yl-methanone(5)

To a solution of 121 g (697 mmol) of 2-fluoro-4-chloromethylbenzaldehydeoxime in 500 ml of dimethyl formamide was added 93 g (697 mmol) ofN-chlorosuccinimide (see K. C. Liu, B. R. Shelton, and R. K. Howe, J.Org. Chem. 1980, 45, 3916). The reaction mixture was stirred at roomtemperature for two hours and then diluted with ethyl acetate. The ethylacetate solution was washed with water, saturated sodium chloride anddried over magnesium sulfate. The drying agent was filtered off andsolvent removed by rotoevaporation to give 130 g (90%) of yellowcrystalline 2-fluoro-4-chloro-N-hydroxybenzenecarboximidoyl chloride.

A mixture of 46.7 g (0.22 mol) of2-fluoro-4-chloro-N-hydroxybenzenecarboximidoyl chloride, 42 g (0.17mol) of 3-(2,4-difluorophenyl)-1-pyridin-3-yl-propynone (3), and 21.76 g(0.26 mol) of sodium bicarbonate in 500 mL of isopropyl alcohol washeated at 85° C. for 21 hours. The reaction mixture was diluted withethyl acetate and washed successively with saturated ammonium chloride,water, and saturate sodium chloride solution, and was dried overmagnesium sulfate. The drying agent was filtered off and the ethylacetate was removed by rotoevaporation. The crude was recrystallisedfrom diethyl ether obtaining the desired product as a yellowish solid(50.28 g, 70.2%).

¹H NMR (CDCl₃): δ 6.75 (m, 1), 7.05 (m, 2), 7.27 (m, 2), 7.67 (t, 1),7.80 (m, 1), 8.03 (m, 1), 8.66 (m, 1) and 8.82 ppm (d, 1). MS m/z: 415(M+H).

(iii) Preparation of[3-(4-chloro-2-fluorophenyl)-5-(2,4-difluorophenyl)isoxazol-4-yl]pyridin-3-yl-methanol(6)

To a solution of 5 (26.5 g, 63.9 mmol) in a mixture of THF/methanol (400ml/40 ml) at 0° C. was added 2.42 g (63.7 mmol) of sodium borohydride.The mixture was stirred for 1.5 hours and then diluted with ethylacetate. The ethyl acetate solution was washed with saturated sodiumchloride solution and dried over magnesium sulfate. The drying agent wasfiltered off and the ethyl acetate was removed by rotoevaporation. Thereaction mixture was purified by column chromatography using a mixtureof heptane/ethyl acetate 1:1. The desired compound was obtained as whitecrystals (17.5 g, 66%). mp=138-140° C.

¹H NMR (CDCl₃): δ 4.19 (bs, 1), 5.89 (s, 1), 6.99 (m, 5), 7.28 (t, 1),7.43 (d, 1), 7.59 (q, 1), and 8.19 (d, 1) and 8.23 ppm (d, 1). MS m/z:417 (M+H).

Example 2(S)-[3-(4-chloro-2-fluorophenyl)-5-(2,4-difluorophenl)isoxazol-4-yl]pyridin-3-yl-methanol

Each enantiomer was isolated by preparative chromatography using theracemic mixture 6 as starting material.

Preparative Method: Column: 250×76 mm CHIRALPAK® AD 20 μm;

Mobil phase: n-heptane/ethanol 70/30 (v/v)Flow rate: 270 ml/min

Detection: UV 280 nm Temperature: 25° C. Analytical Method: Column:250×4.6 mm CHIRALPAK® AD-H 5 μm;

Mobil phase: n-heptane/ethanol/diethylamine 70/30/0.1 (v/v/v)Flow rate: 1 ml/min

Detection: UV 230 nm Temperature: 25° C.

The first eluting enantiomer had a retention time of 7.6 min([α]=+58.07, C=0.025 M, THF) while the second enantiomer had a retentiontime of 9.9 min ([α]=−57.59, C=0.025 M, THF). The second elutingenantiomer is the (S)-enantiomer.

BIOLOGICAL EXAMPLES

The fungicidal properties of Example 2 were demonstrated in thefollowing examples.

Botrytis cinerea (Gray mould): Conidia of the fungus from cryogenicstorage were directly mixed into nutrient broth (PDB potato dextrosebroth). After placing a (DMSO) solution of the test compounds into amicrotiter plate (96-well format) the nutrient broth containing thefungal spores was added. The test plates were incubated at 24° C. andthe inhibition of growth was determined photometrically after 72 hours.Example 2 gave at least 80% control of Botrytis cinerea at 200 ppm.

Mycosphaerella arachidis (syn. Cercospora arachidicola), Brown leaf spotof groundnut (peanut): Conidia of the fungus from cryogenic storage weredirectly mixed into nutrient broth (PDB potato dextrose broth). Afterplacing a (DMSO) solution of the test compounds into a microtiter plate(96-well format) the nutrient broth containing the fungal spores wasadded. The test plates were incubated at 24° C. and the inhibition ofgrowth was determined photometrically after 72 hours at 620 nm. Example2 gave at least 80% control of Mycosphaerella arachidis at 200 ppm.

Septoria tritici (leaf blotch): Conidia of the fungus from cryogenicstorage were directly mixed into nutrient broth (PDB potato dextrosebroth). After placing a (DMSO) solution of the test compounds into amicrotiter plate (96-well format) the nutrient broth containing thefungal spores was added. The test plates were incubated at 24° C. andthe inhibition of growth was determined photometrically after 72 hours.Example 2 gave at least 80% control of Septoria tritici at 200 ppm.

Monographella nivalis (syn. Microdochium nivale, Fusarium nivale), snowmould, foot rot of cereals: Conidia of the fungus from cryogenic storagewere directly mixed into nutrient broth (PDB potato dextrose broth).After placing a (DMSO) solution of the test compounds into a microtiterplate (96-well format) the nutrient broth containing the fungal sporeswas added. The test plates were incubated at 24° C. and the inhibitionof growth was determined photometrically after 72 hours at 620 nm.Example 2 gave at least 80% control of Monographella nivalis at 200 ppm.

Fusarium culmorum (root rot): Conidia of the fungus from cryogenicstorage were directly mixed into nutrient broth (PDB potato dextrosebroth). After placing a (DMSO) solution of the test compounds into amicrotiter plate (96-well format) the nutrient broth containing thefungal spores was added. The test plates were incubated at 24° C. andthe inhibition of growth was determined photometrically after 48 hours.Example 2 gave at least 80% control of Fusarium culmorum at 200 ppm.

Rhizoctonia solani (foot rot, damping-off): Mycelial fragments of thefungus, prepared from a fresh liquid culture, were directly mixed intonutrient broth (PDB potato dextrose broth). After placing a (DMSO)solution of the test compounds into a microtiter plate (96-well format)the nutrient broth containing the fungal mycelium was added. The testplates were incubated at 24° C. and the inhibition of growth wasdetermined photometrically after 48 h. Example 2 gave at least 80%control of Rhizoctonia solani at 200 ppm.

1. A compound of the formula (I)

wherein R¹ is H or acyl; or an agrochemically acceptable salt thereof.2. A compound according to claim 1 wherein R¹ is H.
 3. A compoundaccording to claim 1 which is the (S)-enantiomer of the compound offormula (I).
 4. A compound according to claim 3 which is(S)-[3-(4-chloro-2-fluorophenyl)-5-(2,4-difluorophenyl)isoxazol-4-yl]pyridin-3-yl-methanol


5. A compound according to claim 3 having an enantiomeric excess of (S)to (R) of at least 80%.
 6. A composition comprising a compound accordingto claim 1, or an agrochemically acceptable salt thereof, and anagrochemically acceptable diluent or carrier.
 7. A composition accordingto claim 6 further comprising at least one additional fungicide orsystemically acquired resistance inducer.
 8. A method of controlling orpreventing infestation of cultivated plants, plant propagation material,or a technical material, by pathogenic microorganisms, comprisingapplying a compound according to claim 1, to said plants, parts thereofor the locus thereof, plant propagation material, or technical materialin an amount effective to control said microorganisms.
 9. A methodaccording to claim 9, wherein said plant propagation material comprisesseeds.
 10. A method according to claim 10 wherein the pathogenicmicroorganism is a fungal organism.
 11. A method according to claim 11wherein the fungal organism is selected from Septoria tritici,Stagonospora nodorum, Phytophthora infestans, Botrytis cinerea,Sclerotinia homoeocarpa and Puccinia recondite.
 12. A method of treatinga fungal infection in a subject in need thereof comprising administeringa compound according to claim 1 or a pharmaceutically acceptable saltthereof to said subject in an amount effective to treat said fungalinfection.